The min() operator is pretty much the opposite of the max() operator; it comes in two flavors: with parameter and without parameter. Its task is to find the smallest value. To use it, type:

// mathematical/min.js

let streamOfValues$ = Rx.Observable
  .of(1, 2, 3, 4)
  .min();

// emits 1
streamOfValues$.subscribe(data => console.log(data));